Apparatus for treating material on propeller blades



Sept- 1946- J. o. ANTONSON 2,407,528

APPARATUS FOR TREATING MATERIAL ON PROPELLER BLADES Filed ob 17, 1942 John Uflnfans'an Patented Sept. 10, 1946 APPARATUS .SFQR TREATING MATERIAL TON PRORELLERBLADES John 0. Antonson,

B. Goodrich Company, corporation of New York Akron, Ohio, 'assig'nor to The New York, Y., 2.

Application October 17, 1942, Serial No. 462,372

This invention relates to the treating of material .on elongated structures, and especially to the adhering of protective strips of rubber-like material to the leading 'edges of airplane propeller blades. 7

Protective strips of rubber or other rubberlike material are often desirable on the leading edge of aircraft propeller blades to protect the blade from abrasive contacts, and. to conduct anti-freeze liquid along the leading edgeot-the blade by means of conduits or grooves in such strips to prevent the accumulation of ice on the b1ade.

Heretofore, in attempts to provide for adhering such strips .to the smooth surfaces of blades by means of an air-curing adhesive of rubber or other rubber-like material, difiiculty has been encountered in providing for sufficient adhesion between the rubber-likematerial of the strip and the blade to withstand the effectsof air-flow over the blade, centrifugal .forces, vibrations of the blade, and other forces encountered in operation .of the airplane especially in the presence of severe abrasion. Theproblem ofproviding for successful adhesion under'these conditions has been complicated by the sharpness of the leading edge contours over which the strip is to be conformed and secured. A-lso, an objectionable delay has been necessary after application of such adhesives to permit drying or curing at normal air temperatures and under only the slight pressure of the weight of the protective strip. The difficultie of the problem are complicatedby the fact that the expedient of roughening the smooth surface of a blade may have undesirable effects on the blade structure.

The chief objects of the present invention are to provide means for effectively adhering a strip to the narrow, curved edge or side of thestructure; to provide means for adhering a protective shoe to the leading edge of an aircraft propeller blade in a manner to prevent separation betweenthe shoe and the blade under the forces encountered in use, and to provide apparatus for applying a combination of heat and pressure at the leading edge of a propeller blade to a protective strip of rubber-like material placed thereon to effect attachment between the protective strip and the blade by vulcanization.

Further objects are to provide portability of the apparatus and attachability to a blade in the field and while the blade is on an airplane; to provide apparatus adapted for use interchangeably on variously shaped edge contours; to provide means incorporated in such apparatus for 2 Claims. (01. T5441) forming configurations on the protective strips while adhering the strips to a blade; to provide for durability of structure, and to provide for economy and convenience of manufacture and use. v 4

These and further objects will be apparent from the following description, reference being had to the accompanying drawing in which:

Fig. l isa perspective view of a portion of an airplane propeller and hub assembly having apparatus constructed inaccordance with and embodying the invention moun-ted on a blade thereof, parts being broken away and sectionedfor illustration.

Fig. 2 is a perspective view, partly broken away and sectioned, of a portion of the apparatus of Fig. l, but on an enlarged scale.

Fig. 3 is a view like Fig. 2, but oia modified construction.

Fig. 4 is a view like 2, but of a modified construction. 7

Figs. '5 and 6 are views in cross-section of matrices which may be used in the apparatus.

In the illustrative embodiment of Figs. l and 2 of the drawing, apparatus for applying heat-and pressure to a protective strip of rubber or other rubber-like material on the leading edge of a propeller blade, to attach the strip to the blade effectively by adhesion or vulcanized bond, is indicated generally at Ill. The apparatus i0 is shown mounted on a blade I l of apropeller at the nose of a fuselage or of a motor nacelle of an aircraft, a portion of which is indicated generally at l2 in Fig. 1. p

The apparatus In of this embodiment comrises aheating element 13 of generally U-shape cross-section, as shown, which includes a body '5 4 of yieldable insulating material such for example as rubber or other rubber-like material, compounded for insulation'a-dapted to overlie uni iorrnly a protective strip 55 on the leading edge of the propeller blade H to transfer heat from the element I 3 to adhesive material 11 disposed between the protective strip 15 and the blade H. Heat is supplied to the element !3 preferably by a plurality of resistance wires l6, l6 embedded the body !4 of insulating material. A larger number of wires, or wires of greater heating effeet, is desirable at sections of the blade and material of relatively greater thickness than at sections of relatively less thickness to provide for uniform-penetration and application of heat at all portions of the protective strip. Alter: natively, the heating element l3 may comprise electrically conductive material, such forfexarn further ple as rubber or synthetic rubber or other rubberlike material compounded with graphite, acetylene black, or other suitable electrically conductive material. Lead wires l6a, l6a supply a connection between the heating unit and any suitable source of electricity.

Pressure is applied to the protective strip I preferably by means of an inflatable element l8 of generally V-shape cross-section, as shown, adapted to overlie and press against the heating element l3. The inflatable bly comprises a hollow body of a suitable yieldable material such for example as rubber or other rubber-like material with or without fabric reinforcement and may be expansible or substantially inexpansible, as desired. Air or other pressure fluid may be supplied to the inflatable element l8 as by means of a valve stem I 9, shown in Fig. 1.

, The inflatable bag I8 is restrained at its outward sides as by means of a non-stretchable insulating covering 20 of square-woven fabric or other suitable material for holding the heating element I 3 and the inflatable element l8 on the blade I I, during the application of heat and pressure.

The covering 20, the inflatable bag [8, the heating element l3 and the pad M are preferably assembled on a form of the general shape of the propeller blade or other elongated structure on which the apparatus is to be used so that the pad J4 may be cured in the general shape of the edge of blades of its intended use. The parts of the apparatus [0 are preferably cured or otherwise suitably attached together to provide a unitary structure for convenience of handling in use.

The apparatus l0 ma be mounted on a blade by sliding the uninflated apparatus over the tip of the blade H, enlargement of the space in the bag as a result of deflation making this feasible, or by the provision of a divided construction together with suitable fasteners, such for example as a slide fastener attachment 2|, or by other suitable attaching means.

The insulating material of the heating element may, if, desired, be of a relatively stifl construction, if desired, so that the element will conform substantially to the edge contours of a blade, independently of the pressure applied by the inflatable bag, because of the stifiness of the element.

y In the embodiment of Fig. 3, the apparatus comprises a stiff or rigid metal member 22 of arcuate section enclosing an expansible bag 23 in a manner to restrain expansion of the bag 23 V in the outward direction and to confine such expansion to the inward direction toward the contours of the leading edge of a blade 24 to press against a protective strip 25 disposed along such edge to effect adhesion of the strip 25 to the blade 24.

The expansible bag 23 of this embodiment permits use of the apparatus interchangeably on various shapes of blades and other elongated structure. A suitable heating element 26 is incorporated in the inward surface of the bag 23 to apply heat to the structure for the'attachment of the strip 25 to the blade 24, together with the pressing force of theexpansible bag 23. The heating element 26 may be attached to or molded integral with the bag 23 and may comprise wires 21, 21 embedded in a body 28 of flexible material adapted to conform to various contours of blade edge or elongated structure, or the eleelement [8 prefera-' sure applied by the apparatus 33.

ment may comprise other suitable electrically conductive material, as hereinabove described.

The bag 23 is preferably of such dimensions as to extend beyond the ends of the strip 25 to insure an adequate supply of heat at the ends of the strip 25 and to extend beyond the side mar- 7 blade 24 by any suitable means, as for example by means of one or more straps 29 encircling the apparatus at suitable positions along the blade 24 and secured to projecting flange portions 30 of the arcuate member 22 to secure the apparatus on the blade 24.

In the embodiment of Fig. 4, fins 3|, 3| of metal or other suitable heat and pressure resistant material are incorporated in a heating ele ment 32 in a manner to form grooves in a pro tective strip 34 for conducting anti-freeze liquid along the leading edge of a blade. The fins 3|, 3! may be partially embedded in yield-able material of the element 32 with a sufficient height of fin projecting therefrom to form grooves of the desired depth in the strip 34 under heat and pres- If desired the fins 3| 3| may be provided with flanges, dovetails or other locking portions for further anchorage in the material of the element 32.

If raised ribs are desired 0n the strip 34 for conducting such liquid, suitable corresponding depressions may be provided in the inside surface of heating element 32 to form such ribs. Alternatively, a stiff insert, such for example as the insert 35 shown in Fig. 5 may be used at the inner face of the heating element 32 and this insert may be provided with suitable depressions 36, 36 adapted to form ribs in the material of the strip 34 under heat and pressure. An insert 3'! of suitable shape-retaining material may be provided between the heating element and the protective strip to form grooves in the strip by means of raised portions 38, 38 provided on the insert 31, and may be in the form shown by way of example in Fig. 6. The heatin element 32 may comprise heating wires 39a and an outer layer of insulating material 39, and pressure may be obtained from an inflatable member 40 within the retaining cover 33.

Apparatus of the invention provides for great strength of adhesion or bonding through heat and pressure, and makes possible rapid and convenient installations on an airplane propeller blade in the field, without necessitating the removal of the blade from the airplane. i

Variations may be made without departing from the scope of the invention as it is defined by the following claims.

I claim:

1. Apparatus for treating material on the leading edge of a propeller blade, said apparatus comprising an inflatable flexible walled element generally U-shape in cross section for confining said material between said inflatable element and said leading edge, a heating element generally U-shape in cross-section secured to said inflatable element and located at the inner face of the U-shape inflatable element for positioning adjacent said material, cover means secured to said U-shape inflatable element and extending from the latter element and providing with said latter element a tubular open-ended body adapted to be mounted over the propeller blade entirely around the same,

and means for inflating said U-shape inflatable element to tension said tubular body about said blade while pressing said heating element toward said material.

2. Portable apparatus for treating materia1 on the leading edge of a propeller blade, said apparatus comprising an inflatable flexible Walled element generally U-shape in cross-section for confining said material between said element and said leading edge, an electrical heating element generally U -shape in cross-section secured to said inflatable element and located at th inner face of the U-shape inflatable element for positioning against said material, cover means secured to said U-shape inflatable element and extending from the latter element and providing with said latter element a tubular open-ended body adapted to be mounted over the propeller blade entirely around the same, and means for inflating said U-shape inflatable element to tension said tubular body about said blade While pressing said 0 heating element against said material.

JOHN O. ANTONSON. 

